The present invention relates to clamping assemblies for pile drivers and, more specifically, to clamping assemblies that allow vibratory pile drivers to be connected to caissons for driving caissons into the earth.
Modern construction design often requires caissons to be driven into the earth at desired locations. In the context of the present invention, the term xe2x80x9ccaissonxe2x80x9d will be used to refer to hollow, cylindrical members that are driven into the earth. Caissons are normally used as part of the footing for a structural element such as a building foundation or bridge pier, but the end use of the caisson is not a part of the present invention.
Pile driving systems that impart vibratory loads are highly effective at driving elongate members such as piles, caissons, and the like into the earth. The vibratory forces of such vibratory pile deriving systems must be transmitted to the member to be driven by a clamping assembly. The clamping assembly ensures that the vibratory forces in both directions are applied to the member to be driven.
In the case of caissons, the clamping assembly conventionally comprises a rigid structural member or assembly on which are mounted two or more hydraulic clamps. The hydraulic clamps are spaced from each other along the structural member to grip the upper edge of the caisson such that the vibratory loads are symmetrically applied along the centerline of the caisson.
A basic clamping assembly for relatively small-diameter caissons comprises a single structural member and two hydraulic clamps. The hydraulic clamps are movable along the structural member to allow the clamping assembly to accommodate caissons of different diameters within a range defined by the length of the structural member.
Conventionally, the hydraulic clamps are moved by hand to desired locations on the structural member and fixed. The entire assembly is then lifted to the top of the caisson and displaced such that the top edge of the caisson enters the hydraulic clamps. The clamps are then actuated to grip the caisson and the process of driving the caisson can be commenced.
The need thus exists for improved caisson clamping systems that simplify the process of attaching a vibratory device to a caisson to be driven into the earth.
The following prior art references illustrate the background of the present invention.
U.S. Pat. No. 5,653,556 to White discloses a clamp system for connecting caissons to a vibratory driver/extractor. The clamp system employs a beam assembly that supports four clamps at locations angularly spaced about the circumference of the caisson.
U.S. Pat. No. 5,544,979 to White discloses a clamp system for connecting caissons or piles to a vibratory pile driver/extractor in which the clamp engages a side surface rather than an upper end of the caisson or pile.
U.S. Pat. Nos. 5,117,925 and 5,263,544 to White disclose shock absorbing systems for use with a vibratory pile driver/extractor. These shock absorbing systems could be used with the clamp systems and methods of the present invention.
U.S. Pat. No. 5,609,380 to White discloses a clamp assembly for connecting a vibratory pile/extractor to a pile. Clamping forces are applied to the sides of the pile.
The present invention is a clamp system for allowing a pile driving/pulling system to be attached to a caisson to be driven into or extracted from the earth. The clamp system comprises a structural member, first and second clamp systems, first and second locking systems, and a clamp displacement system. The clamp displacement assembly is operatively connected between the structural member and the first and second clamp assembly. When the first and second clamp systems are disengaged from the pile and the first and second locking systems are disengaged from the structural member, the clamp displacement system may be operated to obtain a desired clamp distance between the first and second clamp assemblies.
Other features and aspects of the present invention will become apparent from the following detailed description of the invention.